Almost 2,000 people, including victims of phone hacking such as Gemma Dowler, the sister of Milly Dowler, are to take part in a simultaneous “thunderclap” Twitter campaign for stronger press regulation.

They will all tweet the same message “Leveson now” at 6pm tonight, Thursday, in the hope that the term will create a spike in hash-tagged terms and appear as a trend on the social network.

In Labour’s case, at 10am on Sunday, 848 people, including party leader Ed Miliband, comedian Eddie Izzard and the actor David Morrissey automatically tweeted: It’s time to deal with David Cameron’s cost of living crisis. Let’s freeze gas and electricity bills. #freezethatbill http://thndr.it/1ixNa2y.

Thunderclap’s statistics show that the tweet made it on to the feed of 4.5 million people, almost exactly as many as watched the BBC News at Ten on Sunday, 3 November.

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